Patent EP0186518A2 successfully refreshed from Google Patents.
EP0186518A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A breakdown protected transistor device
Assignee: Toshiba Corp
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Filing: 1985-12-24
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Granted: —
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Expires: 2005-12-24
Abstract
Abstract A protection circuit is provided- for a bipolar planar transistor device (2). The protection circuit comprises a variable resistor device (6) formed of a junction type field effect transistor (7). The resistor device (6) is connected in series with the base of the planar transistor (2). The drain electrode (11) of the J-FET (7) is connected to the base of the planar transistor (2) while the collector of the planar transistor is connected to the gate of the J-FET. Due to this interconnected scheme, the base input resistance of the planar transistor (2) is increased to reduce its base current when a high voltage is applied accidentally to the collector. The base current is not eliminated, however, and the device (2) is protected but can still operate.
Inventors
- 👤 Kaoru C/O Patent Division Imamura
- 👤 Kenichi C/O Patent Division Muramoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 15:55
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/101; H10D84/121; H10D89/00; H10D89/60
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
A transistor device which will not break down in the event of an accident such as load short circuiting but will continue to operate, said transistor device comprising:- a bipolar transistor (2): and protection means (6) for protecting said bipolar transistor from being damaged due to the accidental application of a high voltage to the collector of said transistor, characterised in that said protection means (6) is responsive to said high voltage to reduce the base current of said transistor (2) without eliminating said base current thereby maintaining the operation of said transistor (2) while protecting said transistor from breaking down.
Claim 2
Dependent Claim
101 words
A transistor device which will not break down in the event of an accident such as load short circuiting but will continue to operate, said transistor device comprising:- a bipolar transistor (2): and protection means (6) for protecting said bipolar transistor from being damaged due to the accidental application of a high voltage to the collector of said transistor, characterised in that said protection means (6) is responsive to said high voltage to reduce the base current of said transistor (2) without eliminating said base current thereby maintaining the operation of said transistor (2) while protecting said transistor from breaking down.
Claim 3
Dependent Claim
21 words
A transistor device according to claim 1 wherein said transistor is a bipolar planar transistor (2) formed on a semiconductor substrate.
Claim 4
Dependent Claim
23 words
A transistor device according to claim 1 or claim 2 wherein said prorection means (6) comprises a junction type field effect transistor (7).
Claim 5
Dependent Claim
48 words
A transistor device according to claim 3 wherein the base of said bipolar planar transistor (2) is connected to the drain (11) of said field effect transistor (7) and the collector of said bipolar planar transistor (2) is connected to the gate of said field effect transistor (7).
Claim 6
Dependent Claim
26 words
A transistor device according to claim 3 as appendant to claim 2, wherein said junction type field effect transistor (7) is formed on said substrate (1).
Claim 7
Dependent Claim
18 words
A transistor device according to claim 5 wherein said substrate (1) functions as said gate and said collector.
Claim 8
Dependent Claim
37 words
A transistor device according to any of claims 3 to 6, wherein said field effect transistor (7) comprises a second gate region (12) which crosses the source region and the drain region of said field effect transistor.
Claim 9
Dependent Claim
35 words
A transistor device according to claim 7, wherein said second gate region (12) is connected to said substrate (1) by a region of a conductivity type other than the conductivity type of said substrate (1).
Claim 10
Dependent Claim
23 words
A transistor device according to claim 7, wherein said second gate region (12) is connected to said substrate (1) by a diode (8).
Claim 11
Dependent Claim
23 words
A transistor device according to claim 9, wherein said second gate region (12) is connected to the anode (17) of said diode (8).
References Cited (Backward Citations)
No citation records indexed.
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